<!DOCTYPE html>
<html>
	<head>
		<meta charset="utf-8">
		<title>const测试</title>
		<h1>测试const用法</h1>
		<ul>
			<li>const一旦定义,不允许被修改</li>
			<li>const定义值时,必须赋初值</li>
			<li>const定义对象时引用不能被修改,但是可以修改对象的属性</li>
		</ul>
	</head>
	<body>
		<script type="text/javascript">
			/* const aa = 100;
			aa = 200; */
			
			/* const aa; */
			
			const user = {
				id : "100",
				name : "tomcat猫"
			}
			
			user.id = 200;
			console.log(user.id);
			
		</script>
		
	</body>
</html>
